InDesign Desktop versions ID20.1, ID19.5.2 and earlier are affected by a NULL Pointer Dereference vulnerability that could result in an application denial-of-service. An attacker could exploit this vulnerability to crash the application, leading to a denial-of-service condition. Exploitation of this issue requires user interaction in that a victim must open a malicious file.
A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit.